(a) Technical Field
The present invention relates to a stop lamp (i.e., brake lamp) drive apparatus. More particularly, it relates to a stop lamp drive apparatus with a simple circuit configuration, which can resolve various limitations such as cost, durability, and malfunctions due to typical complicated circuits and adoption of mechanical contact relays.
(b) Background Art
It is essential for a driver to maintain a safe distance from a vehicle ahead while driving to avoid the possibility of a car accident. Particularly, in vehicles with a high speed drive, the distance between vehicles rapidly and continuously changes due to variation of the relative velocity between them, and thus the driver of a vehicle following from behind should pay close attention to the front vehicle for indications that the front vehicle is going to decelerate or stop (sometimes quickly).
For this reason, stop lamps that light up when a brake pedal is pushed down are provided at the rear of a vehicle. The light emitted by the stop lamps alerts a driver following the vehicle from behind to maintain a safe distance by indicating that the brake pedal is being pushed down by the driver.
In order to turn on/off a stop lamp according to the manipulation of a brake pedal, a switch that is turned on/off at a contact point by the manipulation of the brake pedal is needed. Thus, a stop lamp switch is provided around the brake pedal of a vehicle to turn on/off power from a battery according to the manipulation of the brake pedal.
FIG. 1 shows a view illustrating a circuit configuration of a typical stop lamp drive apparatus, which illustrates a stop lamp switch 20 that is turned on/off according to the manipulation of a brake pedal. In the stop lamp drive apparatus, when a driver manipulates a brake pedal, the stop lamp switch 20 is turned on, and the power from a battery 10 is supplied to the stop lamp 70 that is an end load.
Also, on/off signals of the stop lamp switch 20 can be inputted into various controllers 60 such as an Engine Control Unit (ECU) or Electric Stability Control (hereinafter, referred to as ESC) so that the braking intentions of a driver, i.e., manipulation of a brake pedal, can be reflected in various controls of a vehicle.
Modern vehicles are equipped with an Emergency Stop Signal (ESS) system for alerting the driver of sudden braking, a Downhill Brake Control (DBC) system for allowing a vehicle to slowly go down a hill at a predetermined speed, and a Hillstart Assist Control (HAC) system for preventing a vehicle from moving backward while stopped on the slope of a hill.
Since such ESS, DBC, and HAC systems relate to braking of a vehicle, the operation of the stop lamp 70 is controlled according to the operation (on/off) of the ESS, DBC, and HAC systems. For example, since the ABS ECU or the ESC ECU is involved in the control of the ESS system, a signal according to the operation state (on/off) of the ESS is applied to the stop lamp drive apparatus from the ABS ECU or the ESC ECU. Similarly, since the ESC ECU is involved in the control of the DBC and HAC, a signal according to the operation state (on/off) of the DBC and HAC is applied to the stop lamp drive apparatus from the ESC ECU.
More specifically, a plurality of relays 41 and 42 that are turned on/off by a signal according to the operation state of the ESS, DBC, and HAC, i.e., a relay drive signal of an external controller (ABS/ESC ECU) 50 are disposed in the stop lamp drive apparatus such that the lighting state of the stop lamp 70 can be controlled by the operation state of ESC, DBC, and HAC. In this case, each of the relays 41 and 42 is connected to an output of a stop signal electronic relay module 30 that turns power on/off from a battery according to a signal of the stop lamp switch 20, and selectively applies battery power that is applied through the stop signal electronic relay module 30 according to the operation state signal (relay drive signal) of the ESS, DBC, and HAC of the ABS ECU and ESC ECU that are braking-related controllers to the stop lamp 70 as a load.
As shown in FIG. 1, the relays 41 and 42 may include an ESS relay and an DBC/HAC relay in a typical stop lamp drive apparatus. A contact of each of respective relays 41 and 42 is connected to an output of the stop signal electronic relay module 30 to turn on/off power from a battery, and an exciter thereof is connected to an output of the external controller 50 such as the ABS ECU and the ESC ECU.
However, the stop lamp drive apparatus as configured above has limitations described below.
First, a plurality of mechanical contact relays 41 and 42 are used, and a complicated wiring configuration is needed to connect the contact relays 41 and 42 to the stop signal electronic relay module 31, the respective controllers (ABS ECU and ESC ECU) 50, and the stop lamp 70. This causes an increase in costs of parts and fabrication. Also, since the mechanical contact relays 41 and 42 are used in plurality, there are limitations in durability, damage, and malfunction of the relays. In addition, there is a limitation in terms of reliability and stability of the operation due to a complicated wiring configuration and an increase of the length of wiring that are required.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.